Radio measurement procedure in wireless communication system

ABSTRACT

There is provided a radio measurement procedure for station statistics measurements in wireless communication network. In the method, the requesting station transmits to a requested station a request message for triggered RSNA station statistics measurements including a group identity field which indicates the requested RSNA statistics group and a triggered reporting field for RSNA counters which is used to specify trigger conditions comprising reporting triggers and RSNA statistics thresholds for the corresponding reporting triggers. And, the requesting station receives from the requested station a RSNA statistics measurements report message including measured RSNA statistics for the reporting triggers specified in the triggered reporting field for the RSNA counters when the measured RSNA statistics exceeds the corresponding RSNA statistics thresholds specified in the triggered reporting field for the RSNA counters.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application claims the benefit of Korean Patent Application No.10-2007-0068298 filed on Jul. 6, 2007 in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein in itsentirety by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a wireless communication system, andmore particularly, to a radio measurement procedure for station (STA)statistics in a wireless communication system and a device supportingthe radio measurement procedure.

2. Description of the Related Art

With development of information communication technologies, a variety ofwireless communication technologies have been developed. A wireless LAN(WLAN) is a technology permitting wireless access to Internet inspecific service areas such as home or companies or air planes by theuse of portable terminals such as a personal digital assistant (PDA), alaptop computer, and a portable multimedia player (PMP) on the basis ofa radio frequency technology.

These days, thanks to the increased availability of WLANs, portableterminal users such as laptop computer users are able to perform theirtasks with increased mobility. For example, a user can take his laptopcomputer from his desk into a conference room to attend a meeting andstill have access to his local network to retrieve data and have accessto the Internet via one or more modems or gateways present on the localnetwork without being tethered by a wired connection. Similarly,business travelers commonly use their portable terminals to gain accessto their email accounts, to check if there is any unread email, and toread and send email.

In the initial WLAN technology, a data rate of 1 to 2 Mbps was supportedby the use of frequency hopping, spread spectrum, and infraredcommunication using a frequency of 2.4 GHz in accordance with the IEEE802.11. In recent years, with the development of the wirelesscommunication technology, 54 Mbps in maximum can be supported byapplying the orthogonal frequency division multiplex (OFDM) technology,etc. to the WLAN. In addition, the IEEE 802.11 has developed or isdeveloping wireless communication technologies for improvement inquality of service (QoS), compatibility of an access point (AP)protocol, security enhancement, radio measurement or radio resourcemeasurement, wireless access in vehicular environment, fast roaming,mesh network, inter-working with external networks, wireless networkmanagement, and the like.

In the radio resource measurement procedure, a STA observes the radiolink performance and the radio environment and/or collects data measuredby another STA. The radio resource measurement procedure is performed tounderstand the radio environment. For example, the STA can locallymeasure the radio environment or can request another STA for measuringone or more elements. The STA can receive a request for measuring one ormore elements from another STA and can inform the STA of the measurementresult. The radio measurement data acquired in the procedure can be usedto manage the STA and can be provided to a higher protocol layer forvarious applications.

A variety of means can be used for the radio resource measurement in thewireless network. For example, beacon frames or measurement pilotshaving a predetermined format can be used for the radio resourcemeasurement. A method of calculating a channel load or a noise histogrammay be used therefor. A method using statistical information of STAs canbe used for the radio resource measurement. In this case, valuesrecorded in various counters of the STA or BSS (Basic Service Set)average access delay time can be contained in the statisticalinformation.

SUMMARY OF THE INVENTION

In general, a STA includes plural counters for calculating accumulatedvalues on various kinds of statistical information pieces (hereinafter,referred to as “STA statistic elements”). The STA statistical elementsmeasured by the counters of the STA includes a transmitted fragmentcount, a multicast transmitted frame count, a failure count, a retrycount, a multiple retry count, a frame duplicate count), anacknowledgement failure count, an RTS (Request To Send) success count,an RTS failure count), a discarded frame count), and a transmitted framecount. The STA statistical elements can include a robust securitynetwork association (RSNA) count. Hereinafter, a STA counter formeasuring an RSNA count is referred to as an “RSNA counter”.

In the wireless communication standards, various STA statisticalelements are defined. Since some of the STA statistical elements areclassified into STA statistical elements supporting the quality ofservice (QoS) and STA statistical elements not supporting the QoS formanagement, the number of kinds of the STA statistical elements may bestill greater than described above. Accordingly, a systematic radioresource measurement procedure with high accuracy and efficiency and aradio resource measurement device therefor are required for exchange ofinformation on the STA statistical elements.

A technical goal of the invention is to provide a radio measurementprocedure for STA statistics that can efficiently manage wirelessnetworks by permitting exchange of information on many kinds of STAstatistical elements in a wireless communication system and a devicesupporting the radio measurement procedure.

Another technical goal of the invention is to provide a radiomeasurement procedure for a triggered STA statistical request/reportthat can permit exchange of information on one or more STA statisticalelements only when a specific condition is satisfied in a wirelesscommunication system and a device supporting the radio measurementprocedure.

Still another technical goal of the invention is to provide a messageconstructing method for performing the above-mentioned radio measurementprocedure for a triggered STA statistical request/report.

According to an aspect of the invention, there is provided a radiomeasurement procedure for station statistics measurements in wirelesscommunication network, the radio measurement procedure comprising:transmitting to a requested station a request message for triggered RSNAstation statistics measurements including a group identity field whichindicates the requested RSNA statistics group and a triggered reportingfield for RSNA counters which is used to specify trigger conditionscomprising reporting triggers and RSNA statistics thresholds for thecorresponding reporting triggers; and receiving from the requestedstation a RSNA statistics measurements report message including measuredRSNA statistics for the reporting triggers specified in the triggeredreporting field for the RSNA counters when the measured RSNA statisticsexceeds the corresponding RSNA statistics thresholds specified in thetriggered reporting field for the RSNA counters.

According to another aspect of the invention, there is provided a radiomeasurement procedure for station statistics measurements in wirelesscommunication network, the radio measurement procedure comprising:receiving from a requesting station a request message for triggered RSNAstatistics measurements including a group identity field which indicatesthe requested RSNA group and a triggered reporting field for RSNAcounters which is used to specify trigger conditions comprisingreporting triggers and RSNA statistics thresholds for the correspondingreporting triggers; measuring the requested RSNA statistics; andtransmitting to the requesting station a RSNA statistics measurementsreport message including measured RSNA statistics for the reportingtriggers specified in the triggered reporting field for RSNA counterswhen the measured RSNA statistics exceeds the corresponding RSNAstatistics thresholds specified in the triggered reporting field forRSNA counters.

According to further another aspect of the invention, there is provideda station for supporting radio measurement procedure for stationstatistics measurements in wireless communication network, the stationcomprising: a processor configured to generate and process frames; and atransceiver operably connected to the processor and configured totransmit and receive the frames for the processor, wherein thetransceiver is configured to transmit to a requested station a requestframe for triggered RSNA statistics measurements which is generated bythe processor to include a group identity field indicating the requestedRSNA group and a triggered reporting field being used to specify triggerconditions comprising reporting triggers and RSNA statistics thresholdsfor the corresponding reporting triggers; and receive from the requestedstation a RSNA statistics measurements report message including measuredRSNA statistics for the reporting triggers specified in the triggeredreporting field for RSNA counter when the measured RSNA statisticsexceeds the corresponding RSNA statistics thresholds specified in thetriggered reporting field for RSNA counter.

According to further another aspect of the invention, there is provideda format of triggered reporting field included in measurement requestelement for station statistics measurements procedure in wirelesscommunication network, the triggered reporting field comprising: a RSNAcounter trigger condition subfield being a bit-field that specifiesreporting triggers when requesting triggered station statisticsreporting; and one or more RSNA statistics threshold subfields forspecifying values representing the number of MSDUs to be used as theRSNA statistics threshold values for the corresponding reportingtriggers, and wherein each of the RSNA statistics threshold subfields ispresent when the corresponding bit-field in the RSNA counter triggercondition subfield is set to 1.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages of the present inventionwill become more apparent by describing in detail exemplary embodimentsthereof with reference to the attached drawings in which:

FIG. 1 is a block diagram illustrating a configuration of aninfrastructure basic service set as an example of a wireless LAN system.

FIG. 2 is a block diagram illustrating a configuration of an independentbasic service set as an example of a wireless LAN system.

FIG. 3 is a flowchart illustrating a management procedure of a wirelessnetwork in a wireless communication system according to an embodiment ofthe invention.

FIG. 4 is a message flowchart illustrating a radio measurement procedurefor triggered STA statistics according to an embodiment of theinvention.

FIG. 5 is a diagram illustrating an example of a format of a triggeredradio measurement request frame according to an embodiment of theinvention.

FIG. 6 is a diagram illustrating an example of a format of a triggeredreporting subfield when the triggered radio measurement request frameshown in FIG. 5 is associated with an STA counter.

FIG. 7 is a diagram illustrating an example of a format of a STA countertriggering condition subfield shown in FIG. 6.

FIG. 8 is a diagram illustrating another example of the format of thetriggered reporting subfield when the triggered radio measurementrequest frame shown in FIG. 5 is associated with a QoS STA counter.

FIG. 9 is a diagram illustrating an example of a format of a QoS STAcounter triggering condition field shown in FIG. 8.

FIG. 10 is a diagram illustrating another example of the format of thetriggered reporting subfield when the triggered radio measurementrequest frame shown in FIG. 5 is associated with a RSNA counter.

FIG. 11 is a diagram illustrating an example of a format of a RSNAcounter triggering condition field shown in FIG. 10.

FIG. 12 is a diagram illustrating an example of a format of a triggeredSTA statistical report frame transmitted by a requested STA in step S43of FIG. 4.

FIG. 13 is a diagram illustrating an example of a format of a reportingreason unit shown in FIG. 12.

FIG. 14 is a diagram illustrating another example of the format of thereporting reason unit shown in FIG. 12.

FIG. 15 is a diagram illustrating another example of the format of thereporting reason unit shown in FIG. 12.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will now be described more fully with reference tothe accompanying drawings, in which exemplary embodiments of theinvention are shown. The invention may, however, be embodied in manydifferent forms and should not be construed as being limited to theembodiments set forth herein; rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the concept of the invention to those skilled in the art. Inembodiments and the drawings, respective elements are denoted bydesignation numerals for convenience.

Hereinafter, a management procedure in a wireless communication systemand a station supporting the management procedure according to exemplaryembodiments of the invention will be described in detail with referenceto the accompanying drawings. In the following embodiments, a wirelessLAN (WLAN) system is described as a wireless communication system, butthis is only exemplary. Accordingly, the embodiments to be describedbelow can be applied to wireless communication systems other than theWLAN system, as long as they can be permitted in nature. In this case,terms or words specific to the WLAN system used in the embodiments canbe properly modified into terms or words customarily used in thecorresponding wireless communication system.

FIGS. 1 and 2 schematically show configurations of examples of a WLANsystem to which the embodiments of the invention can be applied.

As shown in FIGS. 1 and 2, a WLAN system includes one or more basicservice sets (BSS). The BSS is a set of stations (STAs) which can besuccessfully synchronized and communicate with each other, but is not aconcept indicating a specific area. The BSS can be classified into aninfrastructure BSS and an independent BSS (IBSS). The former is shown inFIG. 1 and the latter is shown in FIG. 2. The infrastructure BSSs BSS1and BSS2 include one or more STAs STA1, STA2, STA3, and STA4, an accesspoint (AP) which is a STA providing a distribution service, and adistribution system (DS) connecting plural APs AP1 and AP2. On thecontrary, the IBSS does not include an AP and all the STAs are mobilestations STA6, STA7, and STA8. In the IBSS, an access to the DS is notpermitted, thereby constituting a self-contained network.

A STA is a functional unit including a medium access control (MAC)interface and a physical layer interface for a wireless medium inaccordance with the IEEE 802.11 standard and includes both APs andnon-AP stations in a wide meaning. A station for wireless communicationincludes a processor and a transceiver and further includes a userinterface and a display unit. The processor is a functional unitdesigned to generate a frame to be transmitted through a wirelessnetwork or to process a frame received through the wireless network andserves to perform a variety of functions of controlling the station. Thetransceiver is operably connected to the processor and is a unitdesigned to transmit and receive frames through a wireless network.

A portable terminal operated by a user is a non-AP STA (STA1, STA3,STA4, STA6, STA7, and STA8). Simply, a STA may mean a non-AP STA. Thenon-AP STA may be called a wireless transmitting/receiving unit (WTRU),a user equipment (UE), a mobile station (MS), a portable terminal, or amobile subscriber unit.

The AP (AP1 and AP2) is a functional entity providing connection to theDS through a wireless medium for the associated stations. Acommunication between the non-AP STAs in the infrastructure BSSincluding an AP is made through the AP in principle, but the non-AP STAsmay communicate directly with each other when a direct link is set uptherebetween. The AP may be called a convergence controller, a basestation (BS), a node-B, a base transceiver system (BTS), or a sitecontroller, in addition to the tile of an access point.

Plural infrastructure BSSs can be connected to each other through theDS. The plural BSSs connected through the DS are called an extendedservice set (ESS). The STAs in the ESS can communicate with each otherand the non-AP STAs can move from one BSS to another BSS whilecommunicating without any interception.

The DS is a mechanism for allowing an AP to communicate with another AP.Accordingly, the AP can transmit a frame for the STAs associated withthe BSS managed by the AP, forward a frame when a STA moves to anotherBSS, or forward a frame to an external network such as a wired network.The DS may not be a network necessarily, and is not limited in type aslong as it can provide a predetermined distribution service defined inthe IEEE 802.11 standard. For example, the DS may be a wireless networksuch as a mesh network or a physical structure for connecting the APs toeach other.

FIG. 3 is a flowchart illustrating a management procedure of a wirelessnetwork in a wireless LAN system shown in FIG. 1 or 2 or in a wirelesscommunication system including the wireless LAN system or equivalentthereto according to an embodiment of the invention. The flowchart ofoperations between the first STA 2 and the second STA 4 shown in FIG. 3can show a procedure performed between a non-AP STA and an APconstituting an infrastructure BSS, but it is obvious to those skilledin the art that the embodiment is not limited to the procedure. Forexample, the embodiment can be equally or similarly applied tooperations between non-AP STAs in an IBSS, operations between meshpoints (MP) in a mesh network system, or operation between terminals ofdifferent wireless communication systems or between a terminal and abase station, as long as it can be applied thereto in nature.

Referring to FIG. 3, a radio measurement procedure in a wirelesscommunication system according to the embodiment of the inventionfurther includes as preliminary procedures a scanning procedure (S10),an authentication procedure (S20), and/or an association procedure (S30)and further includes a radio measurement procedure (S40) which isperformed after the preliminary procedures S10 to S30. According to theembodiment of the invention, some procedures of the preliminaryprocedures may not be essential but arbitrary.

Referring to FIG. 3, the scanning procedure S10 is first performedbetween the first STA 2 and the second STA 4. The scanning procedure S10is a procedure for allowing the first STA 2 to search for a candidatestation to be associated in the association procedure S30, for example,a procedure for allowing a non-AP STA to search for an AP in theinfrastructure BSS. However, the scanning procedure in a wider meaningmay include a procedure for allowing a non-AP STA to search for aneighboring non-AP STA in the IBSS or a procedure for allowing a non-APSTA to search for a neighboring MP in a mesh network.

The scanning procedure can be classified into two types. One is apassive scanning method using a beacon frame transmitted from the secondSTA 4 and the like. In this method, the first STA 2 to access a wirelessLAN can search for an accessible BSS by receiving a beacon frameperiodically transmitted from the second STA 4 which is an AP managingthe corresponding BSS (or IBSS). The passive scanning method can beapplied when the second STA 4 is an AP transmitting a beacon frame.

The other is an active scanning method. In this method, the first STA 2to access a wireless LAN system, for example, an AP, first transmits aprobe request frame. The second STA 4 having received the probe requestframe transmits a probe response frame including a service set ID (SSID)of the BSS managed by the AP and information on capability supported bythe AP. Accordingly, the first STA 2 can know existence of a candidateAP and a variety of information on the candidate AP from the receivedprobe response frame.

In the scanning procedure S10, when the second STA 4 transmitting thebeacon frame or the probe response frame is a device supporting alocation service, the beacon frame or the probe response frame mayinclude location parameter information elements. The location parameterinformation can include one or more of various information piecesrequired for allowing the first STA 2 having received the beacon frame,etc. to perform the location procedure, such as location indicationparameters, location indication channels, location request options,location service parameters, and radio information pieces.

Referring to FIG. 3, the authentication procedure S20 is performedbetween the first STA 2 and the second STA 4. The authenticationprocedure S20 is a procedure for negotiating an authentication processand an encoding method between entities participating in a wirelesscommunication. For example, the first STA 2 can perform theauthentication procedure S20 with the second STA 4 to be associated ofone or more APs searched for in the scanning procedure S10, for example,an AP. In the WLAN, since an open system authentication method is usedin most cases, the second STA 4 as an AP performs the authenticationprocess without any condition in response to the authentication requestfrom the first STA 2. Reinforced authentication methods include EAP-TLS(Extensible Authentication Protocol-Transport Layer Security), EAP-TTLS(Extensible Authentication Protocol-Tunneled Transport Layer Security),EAP-FAST (Extensible Authentication Protocol-Flexible Authentication viaSecure Tunneling), and PEAP (Protected Extensible AuthenticationProtocol) based on the IEEE 802.1x standard.

When the authentication process is successfully completed in theauthentication procedure S20, the first STA 2 performs the associationprocedure S30. The association procedure S30 may be an arbitraryprocedure which is performed when the first STA 2 is a non-AP STA andthe second STA 4 is an AP. The association procedure S30 is to set up anidentifiable link, that is, a wireless link, between the first STA 2 andthe second STA 4. In the association procedure S30, the first STA 2transmits an association request frame to the second STA 4 havingsuccessfully completed the authentication procedure S20 and the secondSTA 4 transmits to the first STA 2 an association response frame havinga state value of “successful” in response to the association requestframe. The association response frame includes an identifier foridentifying the association with the first STA 2, for example, anassociation ID (AID).

When the association procedure S30 has been successfully completed butthe connection state between the first STA 2 and the second STA 4 isdeteriorated due to a variable channel condition, the first STA 2 canperform the association procedure with another accessible AP again,which is called a re-association procedure. The re-association procedureis very similar to the above-mentioned association procedure S30. Morespecifically, in the re-association procedure, the first STA 2 transmitsa re-association request frame to a different AP (an AP havingsuccessfully completed the authentication procedure S20 among thecandidate APs searched for in the scanning procedure S10) other than theAP currently associated therewith, and the different AP transmits are-association response frame to the first STA 2. However, there-association request frame further includes information on the APpreviously associated therewith and the re-associated AP can transmitdata buffered in the second STA 4, which is an existing AP, using theinformation.

According to the embodiment, in the association procedure S30 or there-association procedure, the association request frame or there-association frame transmitted from the first STA 2 to the second STA4 may include a location capability value of the first STA 2.Accordingly, the first STA 2 supporting the location capability cantransmit the association request frame or the re-association requestframe in which a location descriptor sub-element is included in alocation parameter information element.

Referring to FIG. 3, the radio measurement procedure is performedbetween the first STA 2 and the second STA 4 having completed theauthentication procedure S20 or the association procedure S30 inaddition thereto (S40). Although it has been shown in FIG. 3 that theradio measurement procedure is performed between the first STA 2 and thesecond STA 4 having completed the association procedure S30 in theinfrastructure BSS, the radio measurement procedure S40 described lateraccording to an embodiment of the invention is not limited to thefigure. For example, the radio measurement procedure according to anembodiment of the invention may be performed between the non-AP STA andthe AP shown in FIG. 3, between two peer non-AP STAs setting up a directlink, ore between two peer MPs setting up a mesh link. However, when theradio measurement procedure is performed between the non-AP STAs, theradio measurement procedure can be performed between the non-AP STAssetting up a direct link.

A protocol applicable to the radio measurement procedure according tothe embodiment of the invention will be described in detail. Theprotocol for the radio measurement procedure can be applied to the radioresource measurement procedure of step S40 shown in FIG. 3 or the radiomeasurement procedure for the triggered STA statistic request describedwith reference to FIG. 4 as an example of step S40.

In the wireless network system, a STA can perform a radio measurementprocedure on one or more channels or request one or more different STAsbelonging to the same BSS or IBSS for performing the radio measurementprocedure instead. When it requests another STA for measuring one ormore channel, the requesting STA transmits to the requested STA a radiomeasurement request frame containing one or more measurement requestelements. The radio measurement request frame can be transmitted to therequested STA having an individual address or a group destinationaddress.

In the radio resource measurement procedure, the requesting STA and therequested STA are members of the same infrastructure BSS or IBSS. Theradio measurement request frame having an individual reception addressis transmitted to only the STA setting its radio measurement capabilityin the previous procedures (such as the association procedure S30 inFIG. 3). The measurement request elements included in one radiomeasurement request frame can specify plural measurement types overplural channels.

The STA having transmitted a radio measurement request for measuring anoperating channel to a different STA can transmit the MPDU and the MMPDUto the different STA even in the course of performing the requestedmeasurement. The STA having transmitted a radio measurement request formeasuring a non-operating channel to a different STA need not performany particular action so as to transmit traffics to the different STA.

The measurement results requested by the radio measurement requestelements are included in one or more measurement report elementscorresponding to the request and are reported to the requesting STA.Each measurement report element transmitted in response has the samemeasurement token as included in the corresponding measurement requestelement. The measurement results should be transmitted to the requestingSTA without any improper delay. The measurement report elements areincluded in one or more radio measurement report frame and aretransmitted to the requesting STA. Each radio measurement report framehas the same dialog token as included in the corresponding radiomeasurement request frame.

In the radio measurement procedure in the wireless communication systemaccording to the embodiment of the invention, when the radio measurementtype to be requested is a STA statistic request, a QoS STA statisticrequest, or an RSNA statistic request, a triggered STA statistic requestfor specifying a triggering condition and a threshold value for thestatistic measurement of the triggered STA can be made. That is,according to the embodiment of the invention, by permitting thetriggered STA statistic request for the STA statistic request, the QoSSTA statistic request, or the TSNA statistic request, it is possible toreduce the load on the wireless communication system due to theacquisition of the radio measurement information. According to theembodiment of the invention, this is because it is possible to reducethe load on the requesting STA transmitting the radio measurementrequest frame every time and to reduce an unnecessary signaling in thewireless network system to enhance the use efficiency of the radioresources, by permitting the triggered statistic request for the QoS STAstatistic request and the RSNA statistic request as well as the STAstatistic request.

In this case, the requesting STA can instruct to want to receive atriggered autonomous report by transmitting to a requested STApredetermined information such as a radio measurement request frameincluding a measurement request element of which an enable bit and areport bit are set to “1”. The measurement type to be included in thetriggered autonomous report is instructed by the measurement type fieldof the measurement request element. The triggering condition used tocontrol the triggered autonomous report is included in the radiomeasurement request frame and is transmitted. The measurement requestelements used for the measurement request may be included in the sameradio measurement request frame. The radio measurement request frame maybe transmitted to a group destination address so as to permit theautonomous report triggered by one or more STAs. The requested STA doesnot transmit the autonomous report, when the requested triggeringcondition is not satisfied.

The requested STA having received the radio measurement request framefor requesting the autonomous report triggered by another STA transmitsa proper type of report to the individual address of the requesting STA.That is, in the triggered STA statistic procedure, the requested STAtransmits the autonomous report frame to only the individual address ofthe proper requesting STA when the specified condition is satisfied.

The non-AP STA as the requested STA having received the triggered STAstatistic request including various measurement types can perform pluraltriggered measurement procedures of the plural measurement types. Inthis case, the triggered measurement procedures are logicallyindependent of each other. The reporting conditions such as a triggeredtimeout time are applied to only the measurement request to which it isset.

The radio measurement procedure associated with the triggered STAstatistics in the wireless network system according to the embodiment ofthe invention will be described.

FIG. 4 is a message flowchart illustrating the radio measurementprocedure associated with the triggered STA statistics according to anembodiment of the invention. The radio measurement procedure accordingto the embodiment of the invention is a procedure associated with thetriggered STA statistics for allowing a requesting STA to specify thecondition of reporting the STA statistics collected by the reporting STAor the requested STA for a predetermined time. Here, the “requestingSTA” means an STA transmitting the STA statistic request frame foracquiring the STA statistic information from another STA. The “reportingSTA”, the “measuring STA”, or the “requested STA” means an STAtransmitting the STA statistic report frame including the STA statisticinformation collected in response to the STA statistic request frame tothe requesting STA.

Referring to FIG. 4, the requesting STA (for example, the first STA 2 inFIG. 3) transmits a message for requesting for the conditional STAstatistic report such as a triggered STA statistic request message tothe reporting STA or the requested STA (for example, the second STA 4 inFIG. 3) (S41). The “conditional STA statistic report” means a STAstatistic report to be transmitted when an interested specificstatistics associated with the radio measurement is a defined thresholdvalue. The triggered STA statistic request message has a format in whichinformation for specifying a predetermined triggering condition forallowing a STA having received the message to transmit a report frame inresponse to the measurement request is added to the usual STA statisticrequest message.

The triggered STA statistic request message for requesting another STAfor the STA statistic report may be a frame including STA statisticrequest elements as the measurement request elements. In this case, theSTA statistic request message may be a triggered radio measurementrequest frame.

According to the embodiment of the invention, the triggered radiomeasurement request frame is different from a usual radio measurementrequest frame including the STA statistic request elements not having atriggered reporting subfield, in that the triggered reporting subfieldis further included in the STA statistic request elements as themeasurement request elements included in the triggered radio measurementrequest frame. According to the embodiment of the invention, a statisticgroup of the triggering condition specified in the triggered reportingsubfield may be associated with an STA counter, a QoS STA counter, andan RSNA counter. Accordingly, in the following description, thetriggered radio measurement request frame may be called a triggered STAstatistic frame, a triggered QoS STA statistic request frame, or atriggered RSNA statistic request frame, which is exemplary.

FIG. 5 is a diagram illustrating an example of a format of the triggeredradio measurement request frame 100 according to the embodiment of theinvention. Referring to FIG. 5, the triggered radio measurement requestframe 100 includes a category field 110, an action field 120, a dialogtoken field 130, a number-of-repetitions field 140, and a measurementrequest element field 150. Since the measurement type of the triggeredradio measurement request frame 100 is the STA statistic request, themeasurement request element field 150 includes the STA statistic requestelements. The measurement request field 156 of the STA statistic requestelements additionally includes a triggered reporting subfield 156 d.Now, the elements of the triggered radio measurement request frame 100will be described in detail.

The category field 110 can be set to a value indicating a radiomeasurement category. The action field 120 can be set to a valueindicating the measurement request of radio measurement actions. Thedialog token field 130 can be set to a value other than 0 and selectedby the requesting STA, where the value may be a specific value foridentifying the exchange of the triggered radio measurement requestframe 100 and the radio measurement report frame transmitted in responsethereto.

The number-of-repetitions field 140 is set to a value indicating thenumber of repetitions to be requested to all the measurement requestelements included in the measurement request element field 150 of thetriggered radio measurement request frame 100. When the value is “0”, itindicates that the corresponding measurement request element isperformed only once without repetition. On the contrary, when the valueof the number-of-repetitions field 140 is the largest value (forexample, 65535 when the size of the number-of-repetitions field 140 is 2bytes) which can be included in the number-of-repetitions field 140, itindicates that the corresponding measurement element is performedrepeatedly until the measurement request is cancelled or replaced.

The measurement request element field 150 may not include any or mayinclude plural measurement request elements. The measurement requestelement field 150 includes request details for the statistical elementswhich the requesting STA wants to acquire from the requested STA orrequest details for a specified measurement action which the requestedSTA enters into. The number and length of measurement request elementswhich can be included in the triggered radio measurement request frame100 can be limited by the allowable size of the MMPDU (MAC ManagementProtocol Data Unit). The measurement request element field 150 includesan element ID subfield 151, a length subfield 152, a measurement tokensubfield 153, a measurement request mode subfield 154, a measurementtype subfield 155, and a measurement request subfield 156.

The element ID subfield 151 is set to a value indicating the measurementrequest information elements from various information elements. Thevalue set in the length subfield 152 is variable and depends on thelength of the measurement request subfield 156. The measurement tokensubfield 153 is set to a value other than 0 as a value a specific valueof the measurement request elements transmitted along with the triggeredradio measurement request frame 100. That is, the measurement tokensubfield 153 is used to identify the exchange of the measurement requestelements included in the triggered radio measurement request frame 100and the measurement report elements included in the radio measurementreport frame in response to the measurement request elements.

The measurement request mode subfield 154 is used to indicate how toprocess the request for activating or deactivating the measurementrequest and the autonomous report and includes information indicatingwhether one or more measurement procedures should be started in paralleland whether the measurement is requested or the measurement request iscontrolled, and information indicating the type of the measurementrequest such as the report type in response to the measurement request.The indication of the triggered radio measurement request frame can beperformed by setting the measurement request mode subfield 154 to apredetermined value.

The measurement type subfield 155 is generally set to a value indicatingthe type of the measurement request or the type of the measurementreport. In the triggered radio measurement request frame 100 for the STAstatistics, that is, when the measurement type is the STA statisticrequest, the measurement type subfield 155 is set to a value indicatingthe STA statistic request as the measurement request type.

The measurement request subfield 156 includes detailed information onthe measurement type specified in the measurement type subfield 155. Inthe triggered radio measurement request frame 100 for the STAstatistics, the measurement request subfield 156 can include arandomization interval subfield 156 a, a measurement duration subfield156 b, a group identifier subfield 156 c, and a triggered reportingsubfield 156 d.

The randomization interval subfield 156 a includes a value arbitrarilyspecified in response to the request STA, where the value is used tospecify the upper limit of the measurement start time of the measurementrequest when the measurement is continuously requested. The measurementduration subfield 156 b is generally set to a value indicating a timeinterval for performing the measurement in response to the correspondingrequest. As in the embodiment of the invention, when the triggered radiomeasurement request for the STA statistics is made, the measurementduration subfield 156 b can be set to “0”. The group identifier subfield156 c is set to a value indicating one requested statistical group

Statistics Group Name Group Identity STA Counters fromdot11CountersTable 0 STA Counters from dot11MacStatistics 1 group QoSSTA Counters for UP0 from 2 dot11QosCountersTable QoS STA Counters forUP1 from 3 dot11QosCountersTable QoS STA Counters for UP2 from 4dot11QosCountersTable QoS STA Counters for UP3 from 5dot11QosCountersTable QoS STA Counters for UP4 from 6dot11QosCountersTable QoS STA Counters for UP5 from 7dot11QosCountersTable QoS STA Counters for UP6 from 8dot11QosCountersTable QoS STA Counters for UP7 from 9dot11QosCountersTable BSS Average Access Delays 10 RSNA Counters 11and examples of the value indicating the statistical group is shown inTable 1.Table 1

As can be seen from Table 1, the “STA counters from a counter table (STAcounters from dot11CountersTable)” and the “STA counters from MACstatistic groups (STA counters from dot11MacStatistics group)” arecommon in that they are not associated with the QoS and they areassociated with the STA counters, but are distinguished from each otherin the group identifiers. That is, since the “STA counters from acounter table (STA counters from dot11CountersTable)” and the “STAcounters from MAC statistic groups (STA counters from dot11MacStatisticsgroup)” are different in statistic groups, different group identifiersare used.

The group identifiers of the “STA counters from dot11QosCountersTable”(hereinafter, referred to as “QoS STA counters”) are subdivided by theQoS level (see Group Identifiers 2 to 9). The group identifiers of theQoS STA counters are subdivided and distinguished from each other by theQoS level and are different from the group identifiers of the STAcounters not associated with the group identifiers of the QoS (of whichthe group identifiers are “0” or “1”) or the RSNA counters (of which thegroup identifiers are “16”). The RSNA counters have group identifiersindependent of the STA counters and the QoS STA counters.

Referring to FIG. 1, the triggered reporting subfield 156 d is used tospecify the condition for triggering a report from the requested STA,the value of the triggered timeout, and the threshold values of themeasurement items of the measurement groups of the STA statisticrequest. In general, the triggered reporting subfield 156 d isarbitrarily included in the measurement request field 156. However, asin the embodiment of the invention, in case of the triggered radiomeasurement request frame specifying the condition for reporting the STAcounters (hereinafter, “STA counters” means general STA counters notassociated with the QoS), the QoS STA counters, and the RSNA counters,the triggered reporting subfield 156 d is necessarily included in themeasurement request subfield 156. However, the information included inthe triggered reporting subfield 156 d is different depending on withwhat STA counter the triggered radio measurement request frame isassociated, which is described below.

Triggered Radio Measurement Request Frame Associated with the STACounters

FIG. 6 is a diagram illustrating an example of a format of the triggeredreporting subfield 156 d when the triggered radio measurement requestframe 100 is associated with the STA counters. In the triggeredreporting subfield 156 d having the format shown in FIG. 6, the groupidentifier subfield 156 c of the triggered radio measurement requestframe 100 shown in FIG. 5 is set to the values (the value of the groupidentifiers are 0 or 1 in Table 1) associated with the STA counters.

Referring to FIG. 6, the reporting condition subfield 156 includes theSTA counter triggering condition subfield 210, a measurement countersubfield 218, and a trigger timeout subfield 219 and can include one ormore subfields of a failure threshold subfield 211, a retry thresholdsubfield 212, multiple retry threshold subfield 213, a frame duplicatethreshold subfield 214, an RTS failure threshold subfield 215, an ACKfailure threshold subfield 216, and an FCS error threshold subfield 217.

Among the subfields 211 to 217 for specifying threshold values of theitems of the STA counters, the failure threshold subfield 211 and theFCS error threshold subfield 217 are associated with the groupidentifiers (for example, the group identifiers of “0” in Table 1) ofthe STA counters (hereinafter, referred to as “first STA counters”) fromthe counter table. On the contrary, the other subfields such as theretry threshold subfield 212, the multiple retry threshold subfield 213,the frame duplicate threshold subfield 214, the RTS failure thresholdsubfield 215, and the ACK failure threshold subfield 216 are associatedwith the group identifiers (for example, the group identifiers of “1” inTable 1) of the STA counters (hereinafter, referred to as “second STAcounters”) from the MAC statistic group.

The STA counter triggering condition subfield 210 is used to specify thecondition for triggering the reporting when the triggered radiomeasurement reporting for the STA statistics is requested. In the STAcounter triggering condition subfield 210, one or more triggeringconditions are set along with a specific threshold. The STA countertriggering condition subfield 210 can include plural bit-fields and anexample of the format thereof is shown in FIG. 7.

Referring to FIG. 7, the STA counter triggering condition subfield 210includes a failure bit B0 and an FCS error bit B1 as bits associatedwith the group identifiers (for example, the group identifiers of “0” inTable 1) of the first STA counters and includes a multiple retry bit B2,a frame duplicate bit B3, an RTS failure bit B4, an ACK failure bit B5,and/or a retry bit B6 as the bits associated with the group identifiers(for example, the group identifiers of “1” in Table 1) of the second STAcounters. The bits can be set to “0” or “1”. For example, when a bit isset to “0”, it indicates that it is not necessary to report thecorresponding triggering condition. On the contrary, when a bit is setto “1”, it indicates that the reporting of the corresponding triggeringcondition is requested.

Accordingly, when the bits of the STA counter triggering condition field210 are set to “1”, it means that the generation of the STA statisticreport frame is requested when the value of the corresponding STAcounter is greater than the threshold values defined in thecorresponding subfields 211 to 217. The value of the corresponding STAcounter is measured in the range of the total number of MSDUs in themeasurement count subfield 218.

The requesting STA hoping to receive the triggered report of the STAcounters can set one or more bits (one or more of B0 to B6)corresponding to the condition to “1” in the STA counter triggeringcondition subfield 210 shown in FIG. 7 and can specify a predeterminedthreshold in the threshold subfield of the STA counter itemcorresponding to the bit set to “1” in the STA counter triggeringcondition subfield 210, in the threshold subfields 211 to 217 of the STAcounter items of the triggered reporting subfield 156 d shown in FIG. 6.

The group identifier subfield 156 c in FIG. 5 is set to any one of thegroup identifier values shown in Table 1. On the contrary, the reportingcondition subfield 156 d shown in FIG. 6 and the STA counter triggeringcondition subfield 210 shown in FIG. 7 together include the triggeringconditions associated with two types of statistic groups, that is, thegroup of the first STA counters (for example, the group identifiers of“1” in Table 1) and the group of the second STA counters (for example,the group identifiers of “1” in Table 1). In order to systematically andefficiently the reporting conditions, the value of the STA countertriggering condition subfield 210 shown in FIG. 7 should be set tocorrespond to the value set in the group identifier subfield 156 c.

For example, when the group identifier subfield 156 c is set to “0” asshown in Table 1, it is preferable that the triggering conditionscorresponding to the group of the second STA counters of which the groupidentifiers are “1” cannot be set. Accordingly, when the groupidentifier subfield 156 c is set to “0”, the thresholds of the items ofthe STA counters of which the group identifiers are “1” is not set bysetting to “0” the bits B2 to B6 in the STA counter triggering conditionsubfield 210 shown in FIG. 7. On the contrary, when the group identifiersubfield 156 c is set to “1” as shown in Table 1, the triggeringconditions of the first STA counter group of which the group identifiersis “0” should not be set. Accordingly, when the group identifiersubfield 156 c is set to “1”, the thresholds of the items of the STAcounters of which the group identifiers is “0” is not set by setting to“0” the bits B0 and B1 in the STA counter triggering condition subfield210 shown in FIG. 7.

According to this embodiment, by restricting the values of thebit-fields of the items of the STA counters associated with thenon-corresponding group identifiers in the STA counter triggeringcondition subfield on the basis of the values indicated by the groupidentifiers, it is possible to efficiently construct the STA statisticrequest frame for the STA counters. In addition, according to thisembodiment, by efficiently constructing the STA statistic request frame,it is possible to efficiently and systematically exchange the triggeredSTA statistic request frame and the STA statistic report frame in thetriggered radio measurement procedure.

Referring to FIG. 6, information indicating the number of MSDUs (MACService Data Unit) used to determine whether the measured statistics aregreater than the set thresholds is included in the measurement counterfield 218. Information indicating the time when the measuring STA doesnot generate an additional STA counter statistic report after thetriggering condition is satisfied is included in the trigger timeoutfield 219.

The failure threshold subfield 211 includes a value indicating thenumber of MSDUs used as the threshold of the failure condition. Thefailure threshold subfield 211 is valid only when the failure bit(dot11Failed) of the STA counter triggering condition subfield 210 isset to “1”.

The retry threshold subfield 212 includes a value indicating the numberof MSDUs used as the threshold of the retry condition. The retrythreshold subfield 212 is valid only when the retry bit (dot11Retry) ofthe STA counter triggering condition subfield 210 is set to “1”.

The multiple retry threshold subfield 213 includes a value indicatingthe number of MSDUs used as the threshold of the multiple retrycondition. The multiple retry threshold subfield 213 is valid only whenthe multiple retry bit (dot11MultipleRetry) of the STA countertriggering condition subfield 210 is set to “1”.

The frame duplicate threshold subfield 214 includes a value indicatingthe number of MSDUs used as the threshold of the frame duplicatecondition. The frame duplicate threshold subfield 214 is valid only whenthe frame duplicate bit (dot11FrameDuplicate) of the STA countertriggering condition subfield 210 is set to “1”.

The RTS failure threshold subfield 215 includes a value indicating thenumber of MSDUs used as the threshold of the RTS failure condition. TheRTS failure threshold subfield 215 is valid only when the RTS failurebit (dot11RTSFailure) of the STA counter triggering condition subfield210 is set to “1”.

The ACK failure threshold subfield 216 includes a value indicating thenumber of MSDUs used as the threshold of the ACK failure condition. TheACK failure threshold subfield 216 is valid only when the ACK failurebit (dot11ACKFailure) of the STA counter triggering condition subfield210 is set to “1”.

The FCS error threshold subfield 217 includes a value indicating thenumber of MSDUs used as the threshold of the FCS error condition. TheFCS error threshold subfield 217 is valid only when the FCS error bit(dot11FCSError) of the STA counter triggering condition subfield 210 isset to “1”.

Triggered STA Statistic Request Procedure for QoS STA Counters

Another example of a format of the triggered reporting subfield 156 dshown in FIG. 5 is shown in FIG. 8. In the triggered reporting subfield156 d having the format shown in FIG. 8, the group identifier unit 156 cshown in FIG. 5 is set to a value (one value of the group identifiervalues 2 to 9 shown in Table 1) corresponding to a QoS STA counter.

Referring to FIG. 8, the triggered reporting subfield 156 d includes aQoS STA counter triggering condition subfield 310 (QoS STA CounterTrigger Condition), a QoS failure threshold subfield 311 (dot11QoSFailedThreshold), a QoS retry threshold subfield 312 (dot11QoSRetryThreshold), a QoS multiple retry threshold subfield 313(dot11QoSMultiple Retry Threshold), a QoS frame duplicate thresholdsubfield 314 (dot11QoSFrame Duplicate Threshold), a QoS RTS failurethreshold subfield 315 (dot11QoSRTS Failure Threshold), a QoS ACKfailure threshold subfield 316 (dot11QoSACK Failure Threshold), a QoSdiscard threshold subfield 317 (dot11QoSDiscarded Threshold), ameasurement count subfield 318, and a trigger timeout subfield 319.Here, the threshold subfields 311 to 317 are arbitrary fields that arevalid only when the corresponding bit in the QoS STA counter triggeringcondition subfield 310 is set to “1”.

The QoS STA counter triggering condition subfield 310 is used to specifya condition triggering the reporting when requesting for a triggered QoSSTA statistic report. In the QoS STA counter triggering conditionsubfield 310, one or more triggering conditions are set along with aspecific threshold. The QoS STA counter triggering condition subfield310 can include plural bit-fields, a format of which is shown in FIG. 9.Referring to FIG. 9, the QoS STA counter triggering condition subfield310 includes a QoS failure bit-field B0 (dot11QoSFailed), a QoS retrybit-field B1 (dot11QoSRetry), a QoS multiple retry bit-field B2(dot11QoSMultiple Retry), a QoS frame duplicate bit-field B3(dot11QoSFrame Duplicate), a QoS RTS failure bit-field B4 (dot11QoSRTSFailure), a QoS ACK failure bit-field B5 (dot11QoSACK Failure), and aQoS discard bit-field B6 (dot11QoSDiscarded). The bits can be set to “0”or “1”. When the bit is set to “0”, it indicates that it is notnecessary to report the corresponding triggering condition. On thecontrary, when one or more bits are set to “1”, it indicates that it isrequested to report the corresponding triggering condition.

Accordingly, if the bits of the QoS STA counter triggering conditionsubfield 310 are set to “1”, it means that it is requested to generatethe QoS STA statistic report frame when the value of the correspondingSTA counter is greater than the thresholds defined in the correspondingsubfields 311 to 317. The value of the corresponding STA counter ismeasured within the range of the total number of MSDUs given to themeasurement count subfield 318.

The requesting STA hoping to receive the triggered report of the QoScounters can set one or more bits (one or more of B0 to B6)corresponding to the corresponding condition to “1” in the QoS STAcounter triggering condition subfield 310 shown in FIG. 9 and canspecify a predetermined threshold in the threshold subfield (acorresponding subfield of 311 to 317) corresponding to the bit set to“1” in the triggered reporting subfield 156 d shown in FIG. 8. In thiscase, the group identifier subfield 156 c shown in FIG. 5 is set to oneof the QoS-associated group identifier values shown in Table 1.

Referring to FIG. 8, the measurement count subfield 318 includesinformation indicating the number of MSDUs (MAC Service Data Unit) usedto determine whether the measured statistic is greater than the setthreshold. The trigger timeout subfield 319 includes informationindicating a time when the measuring STA does not generate an additionaltriggered QoS STA statistic report frame after the triggering conditionis satisfied. The QoS threshold subfields 311 to 317 include a valueindicating the number of MSDUs to be used as a threshold of thecorresponding condition.

More specifically, the QoS failure threshold subfield 311 includes avalue indicating the number of MSDUs to be used as the threshold of theQoS failure condition. The QoS failure threshold subfield 311 is validonly when the QoS failure bit (dot11QoSFailed) of the QoS STA countertriggering condition subfield 310 is set to “1”.

The QoS retry threshold subfield 312 includes a value indicating thenumber of MSDUs to be used as the threshold of the QoS retry condition.The QoS retry threshold subfield 312 is valid only when the QoS retrybit (dot11QoSRetry) of the QoS STA counter triggering condition subfield310 is set to “1”.

The QoS multiple retry threshold subfield 313 includes a valueindicating the number of MSDUs to be used as the threshold of the QoSmultiple retry condition. The QoS multiple retry threshold subfield 313is valid only when the QoS multiple retry bit (dot11QoSMultipleRetry) ofthe QoS STA counter triggering condition subfield 310 is set to “1”.

The QoS frame duplicate threshold subfield 314 includes a valueindicating the number of MSDUs to be used as the threshold of the QoSframe duplicate condition. The QoS frame duplicate threshold subfield314 is valid only when the QoS frame duplicate bit(dot11QoSFrameDuplicate) of the QoS STA counter triggering conditionsubfield 310 is set to “1”.

The QoS RTS failure threshold subfield 315 includes a value indicatingthe number of MSDUs to be used as the threshold of the QoS RTS failurecondition. The QoS RTS failure threshold subfield 315 is valid only whenthe QoS RTS failure bit (dot11QoSRTSFailure) of the QoS STA countertriggering condition subfield 310 is set to “1”.

The QoS ACK failure threshold subfield 316 includes a value indicatingthe number of MSDUs to be used as the threshold of the QoS ACK failurecondition. The QoS ACK failure threshold subfield 316 is valid only whenthe QoS RTS failure bit (dot11QoSACKFailure) of the QoS STA countertriggering condition subfield 310 is set to “1”.

The QoS discard threshold subfield 317 includes a value indicating thenumber of MSDUs to be used as the threshold of the QoS discardcondition. The QoS discard threshold subfield 317 is valid only when theQoS discard bit (dot11QoSdiscarded) of the QoS STA counter triggeringcondition subfield 310 is set to “1”.

In this embodiment, the format of the triggered QoS STA statisticrequest frame for the QoS STA counters is specifically subdivided andnewly defined. By using the triggered QoS statistic request frameaccording to this embodiment, the requesting STA can specify one or moretriggering conditions of the subdivided measurement elements for the QoSSTA counters and can request the reporting STA for the statistics.Accordingly, according to this embodiment, it is possible to perform thespecific and systematic triggered QoS STA statistic request and reportprocedures on the measurement elements for the QoS STA counters.

Triggered STA Statistic Request Procedure for RSNA Counters

Another example of a format of the triggered reporting subfield 156 dshown in FIG. 5 is shown in FIG. 10. In the triggered reporting subfield156 d having the format shown in FIG. 10, the group identifier unit 156c shown in FIG. 5 is set to a value (the group identifier value 11 inTable 1) corresponding to an RSNA STA counter.

Referring to FIG. 10, the triggered reporting subfield 156 d includes anRSNA counter triggering condition subfield 410 (RSNA Counter TriggerCondition), a CMACICV error threshold subfield 411(dot11RSNAStatsCMACICVErrors Threshold), a CMAC replay thresholdsubfield 412 (dot11RSNAStatsCMACReplays Threshold), a BIP replaythreshold subfield 413 (dot11RSNAStatsBIPReplays Threshold), a CCMPreplay threshold subfield 414 (dot11RSNAStatsRobustMgmtCCMPReplaysThreshold), a TKIPICV error threshold subfield 415(dot11RSNAStatsTKIPICVErrors Threshold), a TKIP replay thresholdsubfield 416 (dot11RSNAStatsTKIPReplays Threshold), a CCMP decrypt errorthreshold subfield 417 (dot11RSNAStatsCCMPDecryptErrors Threshold), aCCMP replay threshold subfield 418 (dot11RSNAStatsCCMPreplaysThreshold), a measurement count subfield 419, and a trigger timeoutsubfield 420. Here, the threshold subfields 411 to 418 are arbitraryfields that are valid only when the corresponding bit in the RSNAcounter triggering condition subfield 410 is set to “1”.

The RSNA counter triggering condition subfield 410 is used to specify acondition triggering the reporting when requesting for a triggered RSNAstatistic report. In the RSNA counter triggering condition subfield 410,one or more triggering conditions are set along with a specificthreshold. The RSNA counter triggering condition subfield 410 caninclude plural bit-fields, a format of which is shown in FIG. 11.Referring to FIG. 11, the RSNA counter triggering condition subfield 410includes a CMACICV error bit-field B0 (dot11RSNAStatsCMACICVErrors), aCMAC replay bit-field B1 (dot11RSNAStatsCMACReplays), a BIP replaybit-field B2 (dot11RSNAStatsBIPReplays), a CCMP replay bit-field B3(dot11RSNAStatsRobustMgmtCCMPReplays), a TKIPICV error bit-field B4(dot11RSNAStatsTKIPICVErrors), a TKIP replay bit-field B5(dot11RSNAStatsTKIPReplays), a CCMP decrypt error bit-field B6(dot11RSNAStatsCCMPDecryptErrors), and a CCMP replay bit-field B7(dot11RSNAStatsCCMPreplays). The bits can be set to “0” or “1”. When thebit is set to “0”, it indicates that it is not necessary to report thecorresponding triggering condition. On the contrary, when one or morebits are set to “1”, it indicates that it is requested to report thecorresponding triggering condition.

Accordingly, if the bits of the RSNA counter triggering conditionsubfield 410 are set to “1”, it means that it is requested to generatethe RSNA STA statistic report frame when the value of the correspondingRSNA error or failure counter is greater than the RSNA failurethresholds defined in the corresponding subfields 411 to 418. The valueof the corresponding RSNA error or failure counter is measured withinthe range of the total number of MSDUs given to the measurement countsubfield 419.

The requesting STA hoping to receive the triggered report of the RSNAcounters can set one or more bits (one or more of B0 to B7)corresponding to the corresponding condition to “1” in the RSNA countertriggering condition subfield 410 shown in FIG. 11 and can specify apredetermined threshold in the threshold subfield (a correspondingsubfield of 411 to 418) corresponding to the bit set to “1” in thetriggered reporting subfield 156 d shown in FIG. 10. In this case, thegroup identifier subfield 156 c shown in FIG. 5 is set to one of theRSNA-associated group identifier values shown in Table 1.

Referring to FIG. 10, the measurement count subfield 419 includesinformation indicating the number of MSDUs (MAC Service Data Unit) usedto determine whether the measured statistic is greater than the setthreshold. The trigger timeout subfield 420 includes informationindicating a time when the measuring STA does not generate an additionaltriggered RSNA STA statistic report frame after the triggering conditionis satisfied. The RSNA threshold subfields 411 to 418 include a valueindicating the number of MSDUs to be used as a threshold of thecorresponding condition.

More specifically, the CMACICV error threshold subfield 411 includes avalue indicating the number of MSDUs to be used as the threshold of theRSNA statistic CMACICV error condition. The CMACICV error thresholdsubfield 411 is valid only when the CMACICV error bit(dotRSNAStatsCMACICVErrors) of the RSNA counter triggering conditionsubfield 410 is set to “1”.

The CMA replay threshold subfield 412 includes a value indicating thenumber of MSDUs to be used as the threshold of the RSNA statistic CMAreplay condition. The CMA replay threshold subfield 412 is valid onlywhen the CMA replay bit (dotRSNAStatsCMACReplays) of the RSNA countertriggering condition subfield 410 is set to “1”.

The BIP replay threshold subfield 413 includes a value indicating thenumber of MSDUs to be used as the threshold of the RSNA statistic BIPreplay condition. The BIP replay threshold subfield 413 is valid onlywhen the BIP replay bit (dotRSNAStatsBIPReplays) of the RSNA countertriggering condition subfield 410 is set to “1”.

The CCMP replay threshold subfield 414 includes a value indicating thenumber of MSDUs to be used as the threshold of the RSNA statistic CCMPreplay condition. The CCMP replay threshold subfield 414 is valid onlywhen the CCMP replay bit (dotRSNAStatsRobustmgmtCCMPReplays) of the RSNAcounter triggering condition subfield 410 is set to “1”.

The TKIPICV error threshold subfield 415 includes a value indicating thenumber of MSDUs to be used as the threshold of the RSNA statisticTKIPICV error condition. The TKIPICV error threshold subfield 415 isvalid only when the TKIPICV error bit (dotRSNAStatsTKIPICVErrors) of theRSNA counter triggering condition subfield 410 is set to “1”.

The TKIP replay threshold subfield 416 includes a value indicating thenumber of MSDUs to be used as the threshold of the RSNA statistic TKIPreplay condition. The TKIP replay threshold subfield 416 is valid onlywhen the TKIP replay bit (dotRSNAStatsTKIPReplay) of the RSNA countertriggering condition subfield 410 is set to “1”.

The CCMP decrypt error threshold subfield 417 includes a valueindicating the number of MSDUs to be used as the threshold of the RSNAstatistic CCMP decrypt error condition. The CCMP decrypt error thresholdsubfield 417 is valid only when the CCMP decrypt error bit(dotRSNAStatsCCMPDecryptErrors) of the RSNA counter triggering conditionsubfield 410 is set to “1”.

The CCMP replay threshold subfield 418 includes a value indicating thenumber of MSDUs to be used as the threshold of the RSNA statistic CCMPreplay condition. The CCMP replay threshold subfield 418 is valid onlywhen the CCMP replay bit (dotRSNAStatsCCMPReplays) of the RSNA countertriggering condition subfield 410 is set to “1”.

In this embodiment, the format of the triggered STA statistic requestframe for the RSNA counters is specifically subdivided and newlydefined. By using the triggered RSNA STA statistic request frameaccording to this embodiment, the requesting STA can specify one or moretriggering conditions of the subdivided measurement elements for theRSNA counters and can request the reporting STA for the statistics.Accordingly, according to this embodiment, it is possible to perform thespecific and systematic triggered RSNA STA statistic request and reportprocedures on the measurement elements for the RSNA counters.

Referring to FIG. 4 again, the requested STA or the reporting STA havingreceived the STA statistic request message including the triggeredreporting subfield, such as the triggered radio measurement requestframe 100, measures the requested statistics, that is, the statisticelements specified in the triggered reporting subfield 156 d (S42). Themeasurement is performed when the requested STA accepts the triggeredSTA statistic measurement request, and the triggered STA statisticmeasurement request once accepted is continuously valid until therequested STA or the measuring STA is disassociated or is successfullyre-associated. The measurement procedure in the requested STA isperformed within the number of MSDUs included in the measurement countsubfields 218, 318, and 419 of the triggered reporting subfield 156 d.

When the triggering condition is satisfied as the measurement result,the requested STA transmits the requested conditional STA report, thatis, the STA statistic measurement report message, to the requesting STA(S43). The STA statistic measurement report message may be a frameincluding the STA statistic report elements as the measurement reportelements. In this case, the STA statistic report message may be a radiomeasurement report frame.

The requested STA or the measuring STA having transmitted the STAstatistic report message in response to the same triggered STA statisticrequest message does not additionally transmit the STA statistic reportmessage until the trigger timeout period of the triggered STA statisticrequest message expires or until a new triggering condition is requestedand the requested triggering condition is satisfied.

When a different STA statistic measurement request is received in thecourse of the measurement in response to the triggered STA statisticmeasurement report, the procedure for the triggered STA statisticmeasurement request in the course is stopped during the duration of thedifferent STA statistic measurement request. Then, when the triggeredSTA statistic measurement request is restarted, the statisticspreviously counted are reset.

The STA statistics included in the STA statistic report transmitted stepS43 are values accumulated over the transmitted number of MSDUs. Themeasurement duration is not used in the triggered STA statisticmeasurement request and report and the measurement duration included inthe triggered measurement request frame and the triggered measurementreport may be “0”.

All the triggered STA statistic measurement procedures started by therequested STA or the measuring STA are ended by receiving the STAstatistic request message in which the enable bit is set to “1” and thereport bit is set to “0”. The STA transmitting the triggered STAstatistic request message can update the triggering condition bytransmitting a new triggered STA statistic request message forspecifying a new triggering condition.

A block diagram illustrating an example of the format of the triggeredSTA statistic report frame transmitted by the requested STA in step S43is shown in FIG. 12. The frame format shown in FIG. 12 employs an actionframe body format.

Referring to FIG. 12, the triggered STA statistic report frame 500includes a category field 510, an action field 520, a dialog token field530, and a measurement report element field 540. The category field 510is set to a value indicating a radio measurement category, similarly tothe triggered STA statistic request frame 100. The action field 520 isset to a value indicating a measurement report. The dialog token field530 is set to the same value as the dialog token field 130 of thetriggered STA statistic request frame 100. Accordingly, the requestingSTA can know to what request frame the received report frame 500 is aresponse.

The measurement report element field 540 includes one or moremeasurement report elements. The measurement report elements arecollected by the reporting STA and includes a measurement report for therequested elements in which the triggering condition included in thetriggered STA statistic request frame 100 is satisfied. The number andthe lengths of the measurement report elements included in the triggeredSTA statistic report frame 500 are restricted by the size of the MMPDU(MAC Management Protocol Data Unit). The measurement request elementfield 540 includes an element ID subfield 541, a length subfield 542, ameasurement token subfield 543, a measurement report mode subfield 544,a measurement type subfield 545, and a measurement report subfield 546.

The element ID subfield 541 is set to a value indicating the measurementreport element. The value set in the length subfield 542 is variable anddepends on the length of the measurement report subfield 546. Themeasurement token subfield 543 is set to a specific value other than 0between the measurement report elements of the corresponding triggeredSTA statistic report frame 500. The measurement report mode subfield 544is used to indicate specific reasons (such as delay, disable, andrejection) for the failed or rejected measurement request and includesone or more bits. The measurement type field 545 is set to a value foridentifying the measurement report elements 540 and can be set a valueindicating the STA statistic report in this embodiment.

The measurement report subfield 546 includes detailed measurementcontents of the measurement type indicated by the measurement typesubfield 545. The triggered STA statistic report frame 500 can includedetails of the collected or measured STA statistic result. For example,the measurement report subfield 546 is used to report changes of therequested statistic group data measured for the measurement duration.When the measurement duration is 0, the current value is reportedinstead of the changes of the statistic group data. The measurementreport subfield 546 can include a measurement duration unit 546 a, agroup identifier unit 546 b, a statistic group data unit 546 c, and areporting reason unit 546 d.

The measurement duration unit 546 a is set to a value indicating a timeinterval required for calculating the valued measured and included inthe statistic group data unit 546 c, which is a time interval requiredfor the change of the statistic group data. However, when it is thetriggered STA statistic report frame or the current statistic group datais reported, the measurement duration unit 546 a can be set to 0. In thetriggered reporting, the measurement duration unit 546 a can be set to apredetermined value, for example, “65535”.

The group identifier unit 546 b is set to a value indicating therequested statistic group describing the statistic data included in thestatistic group data unit 546 c. An example of the value indicating thestatistic group is shown in Table 1 and one or more statistic valuescollected or measured for each statistic group identifier is included inthe statistic group data unit 546 c. For example, when the value of thestatistic group identifier is “11” indicating the RSNA counter, thereturned statistic values are shown in Table 2.

TABLE 2 Group Identifier Requested Statistics Returned 11dot11RSNAStatsCMACICVErrors (Counter32) dot11RSNAStatsCMACReplays(Counter32) dot11RSNAStatsBIPReplays (Counter32)dot11RSNAStatsRobustMgmtCCMPReplays (counter32)dot11RSNAStatsTKIPICVErrors (counter32) dot11RSNAStatsTKIPReplays(counter32) dot11RSNAStatsCCMPDecryptErrors (counter32)dot11RSNAStatsCCMPReplays (counter32) 12-255 None

The reporting reason unit 546 d is a bit-field indicating a reason fortransmission of the corresponding triggered STA statistic report frame500 from the reporting STA. The reporting reason unit 546 d is anarbitrary subfield which is valid only when the name of the statisticgroup indicated by the group identifier unit 546 b is associated with anon-STA counter, a QoS counter, or an RSNA counter.

Triggered STA Statistic Report Procedure for STA counters

FIG. 13 is a block diagram illustrating an example of a format of thereporting reason unit 546 d, where the group identifier unit 546 b shownin FIG. 12 is set to a value (the group identifier value of 0 or 1 inTable 1) associated with the first and second STA counters. Referring toFIG. 13, the reporting reason unit 546 d includes plural bit-fieldsindicating the reporting reason, such as a failure bit-field(dot11Failed) B0, an FCS error bit-field (dot11FCSError) B1, a multipleretry bit-field (dot11MulipleRetry) B2, a frame duplicate bit-field(dot11FrameDuplicate) B3, an RTS failure bit-field (dot11RTSFailure) B4,an ACK failure bit-field (dot11ACKFailure) B5, and a retry bit-field(dot11Retry) B6.

Triggered STA Statistic Report Procedure for QoS STA Counters

Another example of the format of the reporting reason unit 546 d in FIG.12 is shown in FIG. 14. The unit having the format shown in FIG. 14 isset to a value (one group identifier value of 2 to 9 in Table 1)indicating that the group identifier value shown in FIG. 12 isassociated with the QoS counters. Referring to FIG. 14, the reportingreason unit 546 d includes plural bit-fields indicating the reportingreasons, such as a QoS failure bit-field (dot11QoSFailed) B0, a QoSretry bit-field (dot11QoSRetry) B1, a QoS multiple retry bit-field(dot11QoSMultipleRetry) B2, a QoS frame duplicate bit-field(dot11FrameDuplicate) B3, a QoS RTS failure bit-field(dot11QoSRTSFailure) B4, a QoS ACK failure bit-field(dot11QoSACKFailure) B5, and a QoS discard bit-field (dot11QoSDiscarded)B6.

Triggered STA Statistic Report Procedure for RSNA Counters

Another example of the format of the reporting reason unit 546 d in FIG.12 is shown in FIG. 15. The unit having the format shown in FIG. 15 isset to a value (the group identifier value of 11 in Table 1) indicatingthat the group identifier value shown in FIG. 12 is associated with theRSNA counters. Referring to FIG. 15, the reporting reason unit 546 dincludes plural bit-fields indicating the reporting reasons, such as aCMACICV error bit-field (dot11RSNAStatsCMACICVErrors) B0, a CMAC replaybit-field (dot11RSNAStatsCMACReplays) B1, a BIP replay bit-field(dot11RSNAStatsBIPReplays) B2, a CCMP replay bit-field(dot11RSNAStatsRobustMgmtCCMPReplays) B3, a TKIPICV error bit-field(dot11RSNAStatsTKIPICVErrors) B4, a TKIP replay bit-field(dot11RSNAStatsTKIPReplays) B5, a CCMP decrypt error bit-field(dot11RSNAStatsCCMPDecryptErrors) B6, and a CCMP replay bit-field(dot11RSNAStatsCCMPreplays) B7.

According to the invention, it is possible to permit smooth exchange ofinformation on many kinds of STA statistical elements in a wirelesscommunication system. Particularly, according to some aspects of theinvention, it is possible to efficiently manage the wireless networks bydefining the STA statistical elements on the basis of group identifierinformation specified in a STA statistical request frame.

In some aspects of the invention, since the STA statistical elements arespecified in accordance with a protocol specified at the time ofgenerating a frame, it is possible to efficiently generate and processframes.

While the present invention has been particularly shown and describedwith reference to exemplary embodiments thereof, it will be understoodby those of ordinary skill in the art that various changes in form anddetails may be made therein without departing from the spirit and scopeof the present invention as defined by the following claims.

1. A radio measurement procedure for measuring station statistics in awireless communication network, the radio measurement procedurecomprising: transmitting, to a requested station, a request message fortriggered Robust Security Network Association (RSNA) station statisticsmeasurements, the request message including a group identity field thatindicates a requested RSNA counters statistics group and a triggeredreporting field for RSNA counters that is used to specify triggerconditions and RSNA statistics thresholds; and wherein the triggeredreporting field comprises: an RSNA trigger condition subfield forspecifying reporting triggers, the RSNA trigger condition subfieldcomprising one or more bit-fields for each one of the reportingtriggers; and one or more RSNA statistics threshold subfields forspecifying values representing a number of data units used as RSNAstatistics threshold values for each one of the reporting triggers,wherein the one or more RSNA statistics threshold subfields comprise atleast an RSNA statistics Cipher Based Message Authentication CodeIntegrity Check Value (CMACICV) errors threshold subfield, an RSNAstatistics Cipher Based Message Authentication Code (CMAC) replaysthreshold subfield, an RSNA statistics robust management Counter Modewith Cipher Block Chaining Message Authentication Code Protocol (CCMP)replays threshold subfield, an RSNA statistics Temporal Key IntegrityProtocol Integrity Check Value (TKIPICV) errors threshold subfield, anRSNA statistics Temporal Key Integrity Protocol (TKIP) replays thresholdsubfield, an RSNA statistics CCMP decrypt errors threshold subfield, oran RSNA statistics CCMP replays threshold subfield, and wherein each ofthe RSNA statistics threshold subfields is present when a particularbit-field for each one of the reporting triggers in the RSNA triggercondition subfield is set to 1; and receiving, from the requestedstation, an RSNA statistics measurements report message includingmeasured RSNA statistics when at least one of the trigger conditionsoccurs.
 2. The radio measurement procedure according to claim 1, whereinthe one or more bit-fields are an RSNA statistics CMACICV errorsbit-field, an RSNA statistics CMAC replays bit-field, an RSNA statisticsrobust management CCMP replays bit-field, an RSNA statistics TKIPICVerrors bit-field, an RSNA statistics TKIP replays bit-field, a RSNAstatistics CCMP decrypt errors bit-field, or an RSNA statistics CCMPreplays bit-field.
 3. The radio measurement procedure according to claim2, wherein the triggered reporting field further comprises: ameasurement count subfield including a number of data units fordetermining whether the at least one of the trigger conditions hasoccurred; and a trigger timeout subfield including a value indicating atime period during which the requested station does not generate afurther triggered RSNA statistics measurements report message after theat least one of the trigger conditions has occurred.
 4. The radiomeasurement procedure according to claim 1, wherein: the group identityfield and the triggered reporting field are included in a measurementrequest of a measurement request element; the measurement requestelement further comprises a measurement type set to a value identifyinga station statistics request; and the measurement request element isincluded in a first radio measurement request frame which is the requestmessage.
 5. The radio measurement procedure according to claim 4,wherein the group identity field is set to a value indicating RSNAcounters.
 6. The radio measurement procedure according to claim 4,wherein the measurement request further includes a measurement durationfield which is set to
 0. 7. The radio measurement procedure according toclaim 4, wherein both an enable bit and a report bit within themeasurement request element are set to
 1. 8. The radio measurementprocedure according to claim 7, further comprising: transmitting, to therequested station, a second radio measurement request frame including anRSNA statistics measurement request with an enable bit set to 1 and areport bit set to 0 in order for the requested station to terminate thetriggered RSNA statistics measurement initiated by the first radiomeasurement request frame.
 9. The radio measurement procedure accordingto claim 4, further comprising: transmitting, to the requested station,a second radio measurement request frame including new triggerconditions to update the trigger conditions.
 10. The radio measurementprocedure according to claim 4, wherein: the RSNA statisticsmeasurements report message is a radio measurement report framecomprising a measurement report element; the measurement report elementincludes a measurement type and a measurement report, the measurementtype being set to a value identifying the measurement report; themeasurement report comprises a reporting reason field indicating areason the requested station sent the RSNA statistics measurement reportmessage; and the reporting reason field is a bit-field.
 11. A radiomeasurement procedure for station statistics measurements in wirelesscommunication network, the radio measurement procedure comprising:receiving, from a requesting station, a request message for triggeredRobust Security Network Association (RSNA) statistics measurementsincluding a group identity field that indicates a requested RSNAcounters statistics group and a triggered reporting field for RSNAcounters that is used to specify trigger conditions and RSNA statisticsthresholds; wherein the triggered reporting field comprises: an RSNAtrigger condition subfield for specifying reporting triggers, the RSNAtrigger condition subfield comprising one or more bit-fields for eachone of the trigger reporting triggers; and one or more RSNA statisticsthreshold subfields for specifying values representing a number of dataunits used as RSNA statistics threshold values for each one of thereporting triggers, wherein the one or more RSNA statistics thresholdsubfields comprise at least an RSNA statistics Cipher Based MessageAuthentication Code Integrity Check Value (CMACICV) errors thresholdsubfield, an RSNA statistics Cipher Based Message Authentication Code(CMAC) replays threshold subfield, an RSNA statistics robust managementCounter Mode with Cipher Block Chaining Message Authentication CodeProtocol (CCMP) replays threshold subfield, an RSNA statistics TemporalKey Integrity Protocol Integrity Check Value (TKIPICV) errors thresholdsubfield, an RSNA statistics Temporal Key Integrity Protocol (TKIP)replays threshold subfield, an RSNA statistics CCMP decrypt errorsthreshold subfield, or an RSNA statistics CCMP replays thresholdsubfield, and wherein each of the RSNA statistics threshold subfields ispresent when a particular bit-field for each one of the reportingtriggers in the RSNA trigger condition subfield is set to 1; andmeasuring the requested triggered RSNA statistics; and transmitting tothe requesting station an RSNA statistics measurements report messageincluding the measured triggered RSNA statistics when at least one ofthe trigger conditions occurs.
 12. The radio measurement procedureaccording to claim 11, wherein the one or more bit-fields are an RSNAstatistics CMACICV errors bit-field, an RSNA statistics CMAC replaysbit-field, an RSNA statistics robust management CCMP replays bit-field,an RSNA statistics TKIPICV errors bit-field, a RSNA statistics TKIPreplays bit-field, an RSNA statistics CCMP decrypt errors bit-field, oran RSNA statistics CCMP replays bit-field.
 13. The radio measurementprocedure according to claim 12, wherein the triggered reporting fieldfurther comprises: a measurement count subfield including a number ofdata units for determining whether the at least one of the triggerconditions occurred; and a trigger timeout subfield including a valueindicating a time period during which the requested station does notgenerate a further triggered RSNA statistics measurements report messageafter the at least one of the trigger conditions has occurred.
 14. Theradio measurement procedure according to claim 11, wherein: the groupidentity field and the triggered reporting field for RSNA counter areincluded in a measurement request of a measurement request element; themeasurement request element further comprises a measurement type set toa value identifying a station statistics request; and the measurementrequest element is included in a first radio measurement request framewhich is the request message.
 15. The radio measurement procedureaccording to claim 14, wherein: the measurement request further includesa measurement duration field which is set to 0; and both an enable bitand a report bit within the measurement request element are set to 1.16. The radio measurement procedure according to claim 15, furthercomprising: terminating the triggered RSNA statistics measurementinitiated by the first radio measurement frame in response to receiving,from the requesting station, a second radio measurement request frameincluding an RSNA statistics measurement request with an enable bit setto 1 and a report bit set to
 0. 17. The radio measurement procedureaccording to claim 11, further comprising: updating the triggerconditions in response to receiving, from the requesting station, asecond radio measurement request frame including new trigger conditions.18. The radio measurement procedure according to claim 11 wherein: theRSNA statistics measurements report message is a radio measurementreport frame comprising a measurement report element; the measurementreport element includes a measurement type and a measurement report, themeasurement type being set to a value identifying the measurementreport; the measurement report comprises a reporting reason fieldindicating the reason for sending the RSNA statistics measurement reportmessage; and the reporting reason field is a bit-field.
 19. The radiomeasurement procedure according to claim 11, wherein the measured RSNAstatistics are values accumulated over a number of data unitstransmitted prior to the occurrence of at least one of the triggerconditions.
 20. A station for supporting a radio measurement procedurefor station statistics measurements in wireless communication network,the station comprising: a processor configured to generate and processframes; and a transceiver operably connected to the processor andconfigured to transmit and receive the frames, wherein the transceiveris configured to: transmit, to a requested station, a request messagefor triggered Robust Security Network Association (RSNA) stationstatistics measurements, the request message including a group identityfield that indicates a requested RSNA counters statistics group and atriggered reporting field for RSNA counters that is used to specifytrigger conditions and RSNA statistics thresholds; and wherein thetriggered reporting field comprises: an RSNA trigger condition subfieldfor specifying reporting triggers, the RSNA trigger condition subfieldcomprising one or more bit-fields for each one of the reportingtriggers; and one or more RSNA statistics threshold subfields forspecifying values representing a number of data units used as RSNAstatistics threshold values for each one of the reporting triggers; andwherein the one or more RSNA statistics threshold subfields comprise atleast an RSNA statistics Cipher Based Message Authentication CodeIntegrity Check Value (CMACICV) errors threshold subfield, an RSNAstatistics Cipher Based Message Authentication Code (CMAC) replaysthreshold subfield, an RSNA statistics robust management Counter Modewith Cipher Block Chaining Message Authentication Code Protocol (CCMP)replays threshold subfield, an RSNA statistics Temporal Key IntegrityProtocol Integrity Check Value (TKIPICV) errors threshold subfield, anRSNA statistics Temporal Key Integrity Protocol (TKIP) replays thresholdsubfield, an RSNA statistics CCMP decrypt errors threshold subfield, oran RSNA statistics CCMP replays threshold subfield; and wherein each ofthe RSNA statistics threshold subfields is present when a particularbit-field for each one of the reporting triggers in the RSNA triggercondition subfield is set to 1; and wherein the transceiver is furtherconfigured to: receive, from the requested station, an RSNA statisticsmeasurement report message including measure RSNA statistics when atleast one of the trigger conditions occurs.